I'm 65 years old and have been cooking since early childhood and do all of the home cooking (and food shopping, of course), which is just fine with my wife. I'm also a technical cook and apply a fair amount of science to cooking. But I am always a beginner. Beginners stay open to every sort of new knowledge and always make an effort to improve technique.
The two specific excuses you list are common ones, but they aren't valid excuses. There are indeed those who have limited time to cook. But we are routinely are served meals in restaurants within a few minutes of ordering, and many of them do not require the assistance of heavily prepped ingredients and assistants or high-power equipment. Those with only a few minutes to prepare a meal have to learn appropriate meals and shop for them, but there is no reason to presume the meals are compromised by being quick to prepare.
And if you have a couple of pots and pans, a sharp knife and a heat source capable of boiling water, you have enough equipment. Julia Child's Boeuf Bourguignon that loomed so large in Julie and Julia? Requires what? One skillet, one oven-safe pot, dutch oven, or casserole, a knife and a spoon. If I planned well, I could eliminate the skillet.
There are things that are nice to have. Proper mashed potatoes are unlikely without a ricer or something similar. (If you know the physics of potato cooking, you can get away with a potato masher.) But even if you add the things that are commonly nice to have, the list isn't long or expensive. (I say this, even though I have a bunch of cooking stuff, but you get the idea.) You can cook no end of stunning meals with what you could put in a grocery bag and a camp fire.
You're right, though. Tackling a dish that's really good but pretty unlikely to fail completely, like the salmon, builds confidence. (Salmon presents the classic problem of avoiding overcooking and an opportunity to learn something about your oven.) Even more confidence comes with taking on deceptively simple things that are notoriously easy to screw up and, by screwing up and trying again, become reliable skills. There was at least one acclaimed restaurant where the screening for a prospective new chef was just to make a perfect omelet.
Welcome. It's a journey.
Oh. And here's a tip on salmon. You know that white gunk that tends to ooze out of salmon as it cooks? Can spoil the presentation. It's worst when the fish is cold when the heat is applied and also when high heat is used. Soak the fish for ten minutes in a brine of one tablespoon of salt to a cup of room temp water, rinse and dry. No more white stuff. Works on other fish, too.
The science here is that the salt, which penetrates only the barest surface of the fish, affects the muscle fibers near the surface so that they don't contract and squeeze out the albumen that appears congealed as the white stuff. Plus, the bath tends to bring the fish up to room temperature, which helps.